LOCATION TOLUKOWUK AK
Established Series
SAS/MPS/TJR
02/2022
TOLUKOWUK SERIES
Landscape--hills
Landform--hillslopes
Slope--5 to 25 percent
Parent material--colluvium
Mean annual precipitation--about 500 mm
Mean annual air temperature--about -3 degrees C
Depth class--moderately deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic
TAXONOMIC CLASS: Coarse-loamy, isotic Typic Dystrocryepts
TYPICAL PEDON: Tolukowuk silt loam on a south by southwest facing convex, linear backslope, on a slope of 20 percent at an elevation of 190 m (The soil was dry from 0 to 20 cm and moist throughout the rest of the profile when described on July 11, 2019.)
Oe--0 to 6 cm; moderately decomposed plant material, dark brown (7.5YR 3/4) dry, very dark brown (7.5YR 2.5/3) moist; many very fine, fine, and medium roots; extremely acid (pH 4.0); clear smooth boundary
A--6 to 12 cm; silt loam, dark brown (7.5YR 3/2) dry, very dark brown (7.5YR 2.5/3) moist; weak fine granular structure; very friable, nonsticky, nonplastic; nonsmeary; common very fine and fine, and very few medium roots; common very fine irregular pores; 5 percent subangular gravel; extremely acid (pH 4.3); abrupt wavy boundary
Bw1--12 to 20 cm; gravelly very fine sandy loam, dark yellowish brown (10YR 4/4) dry, dark brown (10YR 3/3) moist; weak thick platy structure; friable, nonsticky, nonplastic; nonsmeary; common very fine roots and very few fine and medium roots; common very fine irregular pores; 15 percent subangular gravel; very strongly acid (pH 5.0); abrupt wavy boundary
Bw2--20 to 63 cm; gravelly loam, light yellowish brown (10YR 6/4) dry, brown (10YR 4/3) moist; moderate medium subangular blocky structure; firm, slightly sticky, nonplastic; nonsmeary; common very fine and very few fine roots; common very fine irregular and common fine irregular pores; 25 percent subangular gravel; strongly acid (pH 5.2); clear smooth boundary
2Cd--63 to 150 cm; very gravelly loam, light yellowish brown (10YR 6/4) dry, brown (10YR 4/3) moist; moderate medium subangular blocky structure; firm, slightly sticky, slightly plastic; nonsmeary; very few fine and very fine roots; common very fine irregular and common fine irregular pores; 40 percent subangular gravel; moderately acid (pH 5.6)
TYPE LOCATION: Yukon-Koyukuk Census Area, Alaska, latitude 63.0256775 longitude -160.5382163 degrees, datum WGS84 (Coordinates determined with a GPS unit)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature-- -1 to 3 degrees C
Soil moisture control section--dry less than 45 consecutive days in June through October
Thickness of ochric epipedon--5 to 18 cm
Thickness of cambic horizon--30 to 85 cm
Depth to densic layer--50 to 100 cm below the mineral soil surface
Particle Size Control Section:
*Clay--8 to 16 percent
*Total fragments--0 to 25 percent gravels
*Sodium fluoride pH--8.4 to 11.6
*Ratio of 1500 kPa water to measured clay--0.6 to 6.0
Oe horizon
Thickness--4 to 10cm
A horizon
Hue--7.5YR or 10YR
Value--2.5 or 3 moist, 4 or 5 dry
Chroma--2 or 3
Fine-earth texture--silt, silt loam
Clay--4 to 10 percent
Sand--10 to 35 percent
Organic carbon--5 to 12 percent
Total rock fragment content--0 to 5 percent gravel
Reaction--4.0 to 5.4
Thickness--6 to 18 cm
Bw1 horizon
Value--3 or 4 moist, 5 or 6 dry
Chroma--3 or 4
Fine-earth texture--silt loam, very fine sandy loam
Clay--5 to 14 percent
Sand--15 to 65 percent
Organic carbon--3 to 5 percent
Total rock fragment content--3 to 15 percent gravel
Reaction--4.7 to 5.6
Thickness--6 to 15 cm
Bw2 horizon
Value--3 or 4 moist, 5 or 6 dry
Chroma--3 or 5
Fine-earth texture--silt loam, loam
Clay--8 to 16 percent
Sand--15 to 50 percent
Organic carbon--3 to 5 percent
Total rock fragment content--3 to 25 percent gravel
Reaction--4.8 to 5.9
Thickness--15 to 45 cm
2Cd horizon
Hue--10YR or 2.5Y
Value--3 or 4 moist, 5 or 6 dry
Chroma--2 or 3
Fine-earth texture--silt loam, loam
Clay--12 to 24 percent
Sand--16 to 50 percent
Organic carbon--0.2 to 1.5 percent
Total rock fragment content--10 to 55 percent
Reaction--5.5 to 6.0
COMPETING SERIES:
*
Blackpoint--no densic layer present
GEOGRAPHIC SETTING:
*Elevation--100 to 350 m
*Climate--warm, moist summers; cold, dry winters
*Mean annual precipitation--450 to 550 mm
*Mean annual air temperature-- -5 to -1 degrees C
*Frost-free period--55 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS:
*
Chiroskey--no densic layer present, hillslopes
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
*Drainage class--well drained
*Saturation during normal years--none
*Saturated hydraulic conductivity (Ksat)--very high in the surface organic layer, high to moderately high throughout the rest of the profile
USE AND VEGETATION:
Use--wildlife habitat, recreation, subsistence
Potential native vegetation--Kenai birch, white spruce, black spruce, Siberian alder, Bebb willow, woodland horsetail, bunchberry dogwood, beauverd spirea, arctic starflower, bluejoint, splendid feather moss, moss, resin birch, bog blueberry, black crowberry, tealeaf willow, stiff clubmoss, sphagnum moss, abietinella moss, Screber's big red stem moss, fireweed, dwarf birch, felt lichen, polytrichum moss, lingonberry, Marsh Labrador tea
DISTRIBUTION AND EXTENT: Nulato Hills-Southern Seward Peninsula Highlands, Alaska; MLRA 240; moderate extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Nulato Hills BLM area, Nome Census Area, Alaska; 2021
REMARKS:
Diagnostic horizons and features recognized in this pedon
*Particle-size control section--zone from 31 to 63cm
*Ochric epipedon--zone from 0 to 12 cm
*Cambic horizon--zone from 12 to 63 cm
*Densic contact--zone from 63 to 150 cm
National Cooperative Soil Survey
U.S.A.